Intracellular pH in sperm physiology

• Sperm intracellular pH regulation is crucial for fertilization.
• Intracellular pH dependent sperm ion channels.
• Importance of sperm specific Na+/H+ exchanger in motility and capacitation.
• Sperm specific Na+/H+ exchanger interacts with soluble adenylyl cyclase.
• Carbonic anhydrase/HCO3− transporter metabolon in sperm function.

Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca2+ channel; Slo3, a K+ channel; the sperm-specific Na+/H+ exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction.